'Decoding the Heavens' by Jo Marchant

Michael Sims

Decoding the Heavens

A 2,000-Year-Old Computer --

and the Century-Long Search to

Discover Its Secrets

Jo Marchant

Da Capo: 328 pp., $25

A friend and I can't discuss archaeology without arguing over the greatest wonder of the ancient world. Is it the crypt of Seti I in the Valley of the Kings, whose grandeur dwarfs the modest resting place of Tutankhamen? No, surely it's the tomb of Qin Shi Huangdi, with its thousands of life-size terra cotta infantry. But what about the ruins of Palenque or Great Zimbabwe? Yet can they compare with Angkor Wat or the Colosseum?

After reading Jo Marchant's marvelous first book, "Decoding the Heavens," I may find myself arguing that our greatest legacy of the past might actually be -- instead of yet another shrine to hubris -- a toaster-size technological memento of just how intelligent some ancient thinkers could be. The very conception of the artifact that experts call the "Antikythera device" is outrageous, aside from its brilliant engineering. Both points deserve emphasis. We may wonder why, for example, the islanders of Rapa Nui sculpted giant heads out of volcanic tuff, but the concept itself doesn't baffle us. There are plenty of unsolved historical mysteries, but most are along the lines of the opaque cipher of the 15th century Voynich manuscript. Few archaeological artifacts compel experts to ask one another, "What exactly is that thing, and how on earth did some ancient whiz kid think of it, much less produce it?"

In her busy, elegant narrative, Marchant asks this question about the Antikythera device -- and, more impressively, she answers it. She reported, in the pages of Nature in 2006, what appears to be the solution to the mystery: how the device's intricate gear systems tracked the different cycles of the sun and moon and the few planets known to the ancient Greeks, as well as the four-year Olympiads. Marchant is not the first person to write about the device, of course. It shows up in most books about ancient technology, alongside diagrams of the mechanical singing birds of Crete and the possibility that the Nazca of Peru invented the first passenger balloons. But until recent technical advances, such as the microfocus X-ray imaging that enabled researchers to literally peer inside the corroded bronze fragments, one hidden layer at a time, scientists were often working with too little data and too much inference -- and, in some cases, a strong leaven of arrogance. Marchant's account is the most up-to-date and the first to document the full story, exploiting discoveries that occurred as recently as 2008.

In her hands, a book that could have been a historical autopsy for tech nerds blossoms into an epic of forgotten geniuses, lost treasure, death-defying underwater exploration and egomaniacal scientists. The Greek island of Antikythera lies in the channel between Crete and the southernmost tip of the Peloponnese. In the ancient world as now, the route saw heavy traffic between the Ionian and Aegean seas. Its violent weather has tormented sailors from Odysseus to Jacques Cousteau (who, incidentally, shows up in this unpredictable narrative), and it has been the grave of countless seafarers. In 1900, a team of gutsy sponge divers was going about its antediluvian business and, supplied with a lifeline from the newly invented hand-cranked air compressor, found on the sea floor astonishing treasures. They included marble and bronze statues, hoards of amphorae and pottery, and a corroded bronze box that -- because of its visible gears -- scientists figured must have come from a later wreck. Only it didn't. It was as old as the rest, dating from the first century A.D. It was the oldest known astronomical instrument and the oldest gear-driven "clockwork" technology by about a millennium.

Thus Marchant launches her account with the birth of underwater archaeology, surely one of the great rousing endeavors still left to us on this paved, mapped planet. By beginning with the artifact's discovery, Marchant keeps her story focused on the quest to decipher the "computer" of her subtitle. Along the way, however, she brings in a great deal of excellent history and science, including the travels of Cicero and the insatiable curiosity of Arthur C. Clarke.

It takes a disciplined brain and a talented writer to explain so many processes with such painless lucidity. Yet, by focusing on the drive and personality of each new character, Marchant keeps the suspense taut as she casually explains the invention of the diving helmet, the way in which nitrogen builds up in the blood and causes the bends, how gear trains interact or how the Babylonians deciphered the varying lunar and planetary cycles. Most important, she makes clear how the Greeks expressed these astronomical relationships via a box of gear-driven indicator dials that must now be accounted one of the ancient wonders of the world.

Sims has written for various publications including American Archaeology and the New Statesman and is the author, most recently, of "In the Womb: Animals From the National Geographic Society."